Objectives: Identifying the factors influencing the survival of hemodialysis patients using a two- stage survival model and longitudinal multivariate in order to provide the therapist with planning to better control elderly hemodialysis patients.
Methods and Materials: The study was a historical cohort study of 395 patients over the age of 60 who underwent hemodialysis. Data were collected over a 15-year period from 2004 to the beginning of 2019 at Hasheminejad Hospital in Tehran. phosphate, calcium, parathormone and creatinine variables have been considered as longitudinal variables and mortality as a survival response in this study. The two-step survival and multivariate model for long-term hemodialysis patients were matched and the results were compared according to the theirs loglikelihood. Data analysis in statistical software R version 3.4 .3 and SAS version 4. 9 was done. The significance level was considered to be 0.05.
Results: Aaverage age of people was 70.41 years and The standard deviation was 6.11. 249 (63%) are male patients. Also, based on (-2 (loglikelihood)), the communication structure between the cumulative effect of longitudinal biological markers and survival, it was selected and considering the subsurface of the estimated random effect chart. And the true value of biomarkers derived from the longitudinal model and assuming other variables are constant, the significance of calcium and log parathormon means that these variables are good indicators over time to determine the occurrence of death in individuals and also per unit increase. In the amount of each of the age variables, the inability to walk, calcium, foot logarithm Atvrmvn, phosphorus and creatinine were risk of dying, 0.993, 1.391, 0.927, 0.967, 0.998, and 0.998 is equal.
Conclusion: By using a two-stage model and selecting a model with a structural relationship between cumulative effect according to fitness, calcium and log parathormone are significant; the survival model in the case of cumulative effect, only the variables of inability to walk, calcium and parathormon are considered as factors affecting the risk of death of hemodialysis patients.